I know that the TV series is roughly paralleling what was in the comics. However, I think if I was in the same situation, I would hightail it out of that prison. The group is outnumbered, is subsisting on a low-calorie diet, is outgunned, and, like Andrea reported to the Governor, they are broken emotionally and mentally. What do they have? Gassed operating vehicles that can get them to safety. And, base on this last episode, the Governor is not devoting resources to containing these individuals, or, otherwise, Rick and his party would never have made it to that other town.
It wouldn't make the story compelling but if it were me, I'd head to the nearest ocean port and find a large yacht, fuel it up, and head to sea. It would be port to port from there and way away from landfall.